1. Field of the Invention
This invention pertains generally to gas turbine driven powerplants, and more particularly to a gas turbine driven powerplant in which a mixture of steam and methane, or another combustible, is reformed or partially oxidized to produce a hydrogen-rich fuel which is used to fuel both the primary combustor and a reheat combustor.
2. Description of the Background Art
Gas turbine driven powerplants that are capable of reheating the gas path between stages of turbine expansion can achieve a significant gain in power output compared to powerplants without reheat capabilities. Raising the gas path temperature generally requires the introduction of a combustible fuel into a reheat combustor. However, reheat combustion using typical gas turbine fuels, such as natural gas or a liquid petroleum fraction, requires a flame holder, a combustion volume for mixing and ignition, and a liner similar to what is required for a typical gas turbine combustor. A further drawback is that these fuels produce additional NOx emissions. Additionally, the gain achieved through reheat combustion implemented in this manner can be negated by the development cost, additional emission controls required, and the additional gas path pressure drop that results. Therefore, there is a need for a gas turbine driven powerplant which includes a reheat combustor which does not require a flame holder, does not entail the development cost associated with turbine cooling, and which requires little or no modification of existing gas turbine engine technology. The present invention satisfies that need, as well as others, and overcomes the deficiencies in conventional reheat technology.